I would tend to agree with Richard, Worms would be a good choice of bait if the rivers high and coloured. They are one of those natural things that get washed into the river during floods. And the fish do tend to get on them. Though you may find the fishing quite hard if you don't know the stretch.
Look for the slacker parts on the bends etc, This is where most of the fish will tend to be. Out of the main flow. and it will be easier to present your bait.. Perseverance is the hardest thing in flood conditions. It can be very frustrating with all the false bites from debris coming down the flow and can be very easy to give up. and go home ,But there's something very rewarding about a flood caught chub or barbel.
One thing i will say and i think Ive said it a few times before, And i speak from personal experience. Flooded rivers are very dangerous places. So watch your step on the banks.